High‐Pressure‐Induced Comminution and Recrystallization of CH₃NH₃PbBr₃ Nanocrystals as Large Thin Nanoplates

Abstract

High pressure (HP) can drive the direct sintering of nanoparticle assemblies for Ag/Au, CdSe/PbS nanocrystals (NCs). Instead of direct sintering for the conventional nanocrystals, this study experimentally observes for the first time high-pressure-induced comminution and recrystallization of organic-inorganic hybrid perovskite nanocrystals into highly luminescent nanoplates with a shorter carrier lifetime. Such novel pressure response is attributed to the unique structural nature of hybrid perovskites under high pressure: during the drastic cubic-orthorhombic structural transformation at ≈2 GPa, (301) the crystal plane fully occupied by organic molecules possesses a higher surface energy, triggering the comminution of nanocrystals into nanoslices along such crystal plane. Beyond bulk perovskites, in which pressure-induced modifications on crystal structures and functional properties will disappear after pressure release, the pressure-formed variants, i.e., large (≈100 nm) and thin (<10 nm) perovskite nanoplates, are retained and these exhibit simultaneous photoluminescence emission enhancing (a 15-fold enhancement in the photoluminescence) and carrier lifetime shortening (from ≈18.3 ± 0.8 to ≈7.6 ± 0.5 ns) after releasing of pressure from 11 GPa. This pressure-induced comminution of hybrid perovskite NCs and a subsequent amorphization-recrystallization treatment offer the possibilities of engineering the advanced hybrid perovskites with specific properties.

Tunable Color Temperatures and Emission Enhancement in 1D Halide Perovskites under High Pressure

“…Pressure, as a clean tuning “knob”, can effectively modulate the distortion degree and crystal structures of LDHPs without changing the chemical composition. [ 9–17 ] The efficient bandgap tuning and emission enhancement in LDHPs render the pressure a robust tool to achieve the optimization of optical properties. [ 18–20 ] However, deep insight into relationship between the distorted formation of octahedral frameworks and controllable emission enhancements of LDHPs still remained obscure as yet.…”

Pressure‐Induced Broadband Emission of 2D Organic–Inorganic Hybrid Perovskite (C6H5C2H4NH3)2PbBr4

“…As a powerful and clean tool, hydrostatic pressure can effectively tune the crystal strucutre and electronic landscapes of 2D perovskite materials without chemical interference; it uniquely accessed novel photophysical and transport properties not accessible by traditional ways, providing a perfect way to confirm our conjecture . In recent years, high pressure research of halide perovskites mainly focused on 3D structure, realizing the fine tuning of optical and electronic properties by lattice compression . Unprecedented simultaneous band‐gap narrowing and carrier lifetime prolongation of FAPbI 3 were achieved by modifying the bond length and bond angle under mild pressure .…”

Pressure‐Induced Emission (PIE) and Phase Transition of a Two‐dimensional Halide Double Perovskite (BA)4AgBiBr8 (BA=CH3(CH2)3NH3+)

“…[5] Pressure is ac lean tuning knob for modulating crystal structures and electronic configurations without changing the chemical composition. [6] In recent years,3 Dh alide perovskites have been studied extensively upon compression, and av ariety of novel phenomena have been observed including pressure-induced phase transformations, [7] amorphization, [8] metallization, [9] band gap modulation, [10] and increased electronic conductivity. [11] However,o nly af ew studies on 2D halide perovskites with compression have been reported thus far.…”